Similar histopathological picture in males with Achilles and patellar tendinopathy

PURPOSE: To ascertain whether there are differences in the histopathological appearance of tendinopathic Achilles and patellar tendons. METHODS: In males, we studied biopsies from tendinopathic Achilles (N = 28; average age 34.1 yr) and patellar tendons (N = 28; average age 32.1), Achilles tendons (N = 21; average age 61.8 yr) from deceased patients with no known tendon pathology, and patellar tendons (N = 15; average age 28.3) from patients undergoing anterior cruciate ligament reconstruction. Hematoxylineosin stained slides were interpreted using a semiquantitative grading scale (0: normal to 3: maximally abnormal) for fiber structure, fiber arrangement, rounding of the nuclei, regional variations in cellularity, increased vascularity, decreased collagen stainability, and hyalinization. All slides were assessed blindly twice, the agreement between two readings ranging from 0.170 to 0.750 (kappa statistics). RESULTS: The highest mean score of tendinopathic Achilles tendons was not significantly different from that of tendinopathic patellar tendons (11.6 +/- 5 and 10.4 +/- 3, respectively). The ability to differentiate between an Achilles tendon and a patellar tendon was low. CONCLUSIONS: Tendinopathic Achilles and patellar tendons show a similar histological picture. It was not possible to identify whether a specimen had been harvested from an Achilles or a patellar tendon on the basis of histological examination. The general pattern of degeneration was common to both tendinopathic Achilles and patellar tendons. A common, as yet unidentified, etiopathological mechanism may have acted on both these tendon populations.     

Ruptured Achilles tendons show increased lectin stainability

PURPOSE: To ascertain whether lectins could be a useful tool for investigation of the extracellular matrix of degenerated and normal tendons. METHODS: Hematoxylin-eosin-stained slides were assessed blindly using a semiquantitative grading scale for fiber structure, fiber arrangement, rounding of the nuclei, regional variations in cellularity, increased vascularity, decreased collagen stainability, hyalinization, and glycosaminoglycan, with a pathology score giving up to three marks per each of the above variables, with 0 being normal and 3 being maximally abnormal. For lectin staining with Aleuria aurantia, Canavalia ensiformis, Galanthus nivalis, Phaseolus vulgaris, Arachis hypogea, Sambucus nigra, and Triticum vulgaris, assessment of staining on a scale from 0 (no staining) to 5 (strong staining) was performed blindly. RESULTS: The mean pathology sum score of ruptured tendons (N = 14; average age 46.5 yr, range 29-61) was significantly greater than the mean pathology score of the control tendons of Achilles tendons from individuals with no known tendon pathology (N = 16; average age 62.5 yr, range 49-73) (pathology score: 18.5 +/- 3.2 vs 6.1 +/- 2.3). Four of the seven lectins used exhibited significantly positive results. CONCLUSIONS: Ruptured tendons were histologically significantly more degenerated than control tendons. Ruptured tendons showed different lectin staining properties than nonruptured ones. This difference may have resulted from posttranslational changes in the extracellular matrix producing alterations in the biochemistry of the tendon, which might interfere with the interaction with the lateral sugar residues of the collagen molecules or cause steric blockade.     

Marked pathological changes proximal and distal to the site of rupture in acute Achilles tendon ruptures

A laboratory study was performed to evaluate the histopathological features of the macroscopically intact portion of the Achilles tendon in patients undergoing surgery for an acute rupture of the Achilles tendon. Tendon samples were harvested from 29 individuals (21 men, 8 women; mean age: 46 ± 12) who underwent repair of an Achilles tendon tear tear, and from 11 male patients who died of cardiovascular events (mean age: 61). Three pieces of tendon were harvested: at the rupture site, 4 cm proximal to the site of rupture, 1 cm proximal to the insertion of the Achilles tendon on the calcaneum. Slides were assessed using a semiquantitative grading scale assessing fiber structure and arrangement, rounding of the nuclei, regional variations in cellularity, increased vascularity, decreased collagen stainability, and hyalinization. Intra-observer reliability of the subscore readings was calculated. The pathological features were significantly more pronounced in the samples taken from the site of rupture than in the samples taken proximally and distal to it (0.008 < P < 0.01). There were no significant differences in the mean pathologic sum-scores in the samples taken proximally and distal to the site of rupture. Unruptured Achilles tendons, even at an advanced age, and ruptured Achilles tendons are clearly part of two distinct populations, with the latter demonstrating histopathological evidence of failed healing response even in areas macroscopically normal.     

Eccentric training of the gastrocnemius-soleus complex in chronic Achilles tendinopathy results in decreased tendon volume and intratendinous signal as evaluated by MRI

BACKGROUND: Satisfactory treatment results have been reported after eccentric calf muscle strength training in patients with chronic Achilles tendinopathy. HYPOTHESIS: Magnetic resonance imaging may be a useful adjunct in the evaluation of the effect of 3 months of eccentric calf muscle strength training. STUDY DESIGN: Prospective cohort study. METHODS: Using magnetic resonance imaging, the Achilles tendons were investigated in 25 patients (16 men and 9 women) ranging in age from 28 to 70 years (median, 51 years) before and after training. Five different magnetic resonance imaging sequences were used. Tendon volume and mean intratendinous signal were calculated using a new seed-growing technique showing 99.3% and 96.6% intraobserver reliability, respectively. The clinical outcome was categorized according to pain level and performance using a questionnaire completed by the patient. RESULTS: The eccentric training resulted in a 14% (mean) decrease of tendon volume measured on T1-weighted images, from 6.6 +/- 3.1 cm3 to 5.8 +/- 2.3 cm3 (P < .05). The intratendinous signal in the symptomatic Achilles tendon measured on proton density-weighted images decreased 23% (mean), from 227 +/- 77 signal units to 170 +/- 83 signal units (P < .05). The gadolinium contrast agent-enhanced images did not add further value compared with other sequences. CLINICAL OUTCOME: The clinical outcome was categorized as excellent in 10, good in 3, fair in 5, and poor in 8 patients. The Delta signal correlated significantly with the pain level (P < .05). CONCLUSIONS: Eccentric training resulted in decreased tendon volume and intratendinous signal and was correlated with an improved clinical outcome. Magnetic resonance imaging techniques can be used as an adjunct to clinical evaluation by monitoring morphologic effects in clinical treatment studies of Achilles tendinopathy.     

Eccentric training in patients with chronic Achilles tendinosis: normalised tendon structure and decreased thickness at follow up

OBJECTIVE: To prospectively investigate tendon thickness and tendon structure by ultrasonography in patients treated with eccentric calf muscle training for painful chronic Achilles tendinosis located at the 2-6 cm level in the tendon. METHODS: The patients were examined with grey scale ultrasonography before and 3.8 years (mean) after the 12 week eccentric training regimen. At follow up, a questionnaire assessed present activity level and satisfaction with treatment. RESULTS: Twenty six tendons in twenty five patients (19 men and six women) with a mean age of 50 years were followed for a mean of 3.8 years (range 1.6-7.75). All patients had a long duration of painful symptoms (mean 17.1 months) from chronic Achilles tendinosis before treatment. At follow up, 22 of 25 patients were satisfied with treatment and active in Achilles tendon loading activities at the desired level. Ultrasonography showed that tendon thickness (at the widest part) had decreased significantly (p<0.005) after treatment (7.6 (2.3) v 8.8 (3) mm; mean (SD)). In untreated normal tendons, there was no significant difference in thickness after treatment (5.3 (1.3) mm before and 5.9 (0.8) mm after). All tendons with tendinosis had structural abnormalities (hypoechoic areas and irregular structure) before the start of treatment. After treatment, the structure was normal in 19 of the 26 tendons. Six of the seven patients with remaining structural abnormalities experienced pain in the tendon during loading. CONCLUSIONS: Ultrasonographic follow up of patients with mid-portion painful chronic Achilles tendinosis treated with eccentric calf muscle training showed a localised decrease in tendon thickness and a normalised tendon structure in most patients. Remaining structural tendon abnormalities seemed to be associated with residual pain in the tendon.     

Chondral metaplasia in calcific insertional tendinopathy of the Achilles tendon.

OBJECTIVE: To ascertain whether tendon samples harvested from patients with calcific insertional Achilles tendinopathy showed features of failed healing response, and whether abnormal quantities of type II collagen had been produced in that area by these tenocytes. DESIGN: Comparative laboratory study. DESIGN: University teaching hospitals. PATIENTS: Tendon samples were harvested from eight otherwise healthy male individuals (average age 47.5+/-8.4 years, range 38 to 60) who were operated for calcific insertional Achilles tendinopathy and from nine male patients who died of cardiovascular events (mean age 63.1+/-10.9 years) while in hospital. INTERVENTIONS: Open surgery for calcific insertional Achilles tendinopathy. MAIN OUTCOME MEASURE: Semi-quantitative histochemical, immunohistochemical, and immunocytochemical methods to ascertain whether tendinopathic tendons were morphologically different from control tendons, and whether abnormal types of collagen were produced. RESULTS: Tenocytes from tendons from patients with calcific insertional Achilles tendinopathy exhibit chondral metaplasia, and produce abnormally high quantities of collagen type II and III. CONCLUSIONS: The altered production of collagen may be one reason for the histopathological alterations described in the present study. Areas of calcific insertional Achilles tendinopathy have been subjected to abnormal loads. These tendons may be less resistant to tensile forces. Further studies should investigate why some tendons undergo these changes.     

Achilles tendon and paratendon microcirculation in midportion and insertional tendinopathy in athletes

BACKGROUND: Neovascularisation can be detected qualitatively by Power Doppler in Achilles tendinopathy. Quantitative data regarding tendon microcirculation have not been established and may be substantial. PURPOSE: To assess the microcirculation of the Achilles tendon and the paratendon in healthy volunteers as well as in athletes with either midportion or insertional tendinopathy. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: In 66 physically active volunteers, parameters of Achilles tendon and paratendon microcirculation, such as tissue oxygen saturation, relative postcapillary venous filling pressures, and microcirculatory blood flow, were determined at rest at 2-mm and 8-mm tissue depths. Forty-one patients never had Achilles pain (25 men, 27 +/- 8 years), 14 patients had insertional pain (7 men, 29 +/- 8 years), and 11 patients had midportion tendinopathy (7 men, 38 +/- 13 years, not significant). RESULTS: Achilles tendon diameter 2 cm and 6 cm proximal to the insertion was increased in symptomatic tendons. Compared with the uninvolved opposite tendon, deep microcirculatory blood flow was significantly elevated at insertional (160 +/- 79 vs 132 +/- 42, P < .05) as well as in midportion tendinopathy (150 +/- 74 vs 119 +/- 34, P < .05). The microcirculation in the uninvolved opposite tendon and the normal athlete controls were not significantly different from each other (132 +/- 42 insertional asymptomatic vs 119 +/- 34 mid-portion vs 120 +/- 48 healthy tendon). Insertional paratendon deep microcirculatory flow was elevated in all groups, whereas tissue oxygen saturation and relative postcapillary venous filling pressures were not significantly different. CONCLUSION: Microcirculatory blood flow is significantly elevated at the point of pain in insertional and midportion tendinopathy. Postcapillary venous filling pressures are increased at both the midportion Achilles tendon and the midportion paratendon, whereas tissue oxygen saturation is not different among the studied groups. We found no evidence of an abnormal microcirculation of the asymptomatic limb in Achilles tendinopathy.     

Is vasculo-neural ingrowth the cause of pain in chronic Achilles tendinosis?

The purpose of this study was to investigate where the pain comes from in chronic mid-portion Achilles tendinosis, by using ultrasonography and colour Doppler, immunohistochemistry, and diagnostic injections. Twenty-five tendons in 24 patients (mean age 47 years) with the clinical diagnosis of painful chronic mid-portion Achilles tendinosis, and 20 tendons in 14 controls (mean age 48 years) with pain-free Achilles tendons were examined with ultrasonography and colour Doppler. For the 25 painful tendons, a local anaesthetic was injected in the area with neovascularisation outside the ventral part of the tendon. Biopsies taken from tendinosis tissue in six patients were used for PGP 9.5 immunohistochemistry. A neovascularisation, inside and outside the ventral part of the area with tendon changes, was demonstrated in all painful tendinosis tendons, but not in any of the pain-free control tendons. After injection of the local anaesthetic towards the neovessels outside the ventral part of the tendon, the pain during tendon-loading activity was temporarily cured in all patients. The mean VAS-score for heel-raises decreased significantly from 75 mm to 6 mm. In biopsies, PGP 9.5 immunohistochemistry showed nerve structures in the vicinity of blood vessels. In conclusion, we demonstrate findings which support neovessels and accompanying nerves being the possible source of pain in chronic mid-portion Achilles tendinosis.     

Effect of habitual exercise on the structural and mechanical properties of human tendon, in vivo, in men and women

We examined whether long-term habitual training (a) was associated with differences in structural and mechanical properties in tendon in women and (b) yielded different tendon properties in men and women. Ten male runners, 10 female runners and 10 female non-runners were tested. Tendon cross-sectional area (CSA) and length of the patellar and Achilles tendon were determined with MRI. Ultrasonography-based measurement of tendon elongation and force during isometric contractions provided mechanical properties. Distal patellar and Achilles tendon CSAs were greater than the proximal part in all three groups (P<0.05). Weight-normalized Achilles tendon CSA were similar in trained (2.78+/-0.17 mm(2)/kg(3/4)) and untrained women (2.60+/-0.13 mm(2)/kg(3/4)), while that in trained men (3.77+/-0.27 mm(2)/kg(3/4)) was greater compared with trained women (P<0.01). Patellar tendon CSA were comparable in trained and untrained women, while that in trained men was greater compared with trained women (P<0.01). Patellar tendon stiffness was greater in male runners (3528+/-773 N/mm) compared with female runners (2069+/-666 N/mm) and non-runners (2477+/-381 N/mm), (P<0.01), but patellar tendon deformation, stress, strain and modulus were similar. These data indirectly suggest that the ability of Achilles and patellar tendons to adapt in response to habitual loading such as running is attenuated in women.     

Immediate Achilles tendon response after strength training evaluated by MRI

PURPOSE: To evaluate the tendon response after acute strength training in chronic Achilles tendinosis using magnetic resonance imaging (MRI). METHODS: Twenty-two patients (44 Achilles tendons, 15 males, 8 patients with bilateral symptoms) with a median age of 45 yr (range 28-57 yr) were included in the study. In all patients, both Achilles tendons were examined with MRI before and immediately after a standardized training program. The most painful side underwent 6 sets and 15 repetitions of heavy-loaded eccentric training. The contralateral tendons underwent only concentric loading during the training program. The tendon volume and the intratendinous signal were evaluated and calculated by MRI using a seed-growing technique. RESULTS: The immediate response of eccentric loading on the symptomatic tendons resulted in a 12% increase of the tendon volume, evident on T2-WI, from 7.8 +/- 2.0 to 8.8 +/- 2.7 cm3 (P < 0.001), and a 31% increase of the intratendinous signal evident on PD-WI, from 221 +/- 74 to 278 +/- 78 signal units (SU) (P < 0.001). The corresponding sequences on the contralateral concentrically loaded tendons showed an increase of 17% of tendon volume, from 6.1 +/- 1.5 to 7.0 +/- 1.6 cm3 (P < 0.001), and an increase of 27% of the intratendinous signal, from 170 +/- 55 to 211 +/-57 SU (P < 0.001). There was no significant difference of the mean of the increased tendon volume and the intratendinous signal between the eccentrically heavily loaded symptomatic tendons and the concentrically loaded contralateral tendons. CONCLUSIONS: Both eccentric and concentric loading of the Achilles tendon resulted in increased total tendon volume and intratendinous signal. This increase may be explained by a higher water content and/or hyperemia in the Achilles tendon during and/or immediately after strength training of the gastrocnemius-soleus complex.     

Bilateral Achilles tendon rupture: a report on two cases

Two cases of traumatic bilateral Achilles tendon rupture are reported. One of the patients was a healthy middle-aged man, who had been an active nationallevel gymnast 20 years earlier. He had not suffered any complaints of Achilles tendons before. The ruptures occurred when, after a sauna, he showed his guests a vault forwards, which he had been able to perform easily. This time the landing took place on the toes, causing a high peak stretch to the calf muscles and Achilles tendons. The total rupture of both Achilles tendons was treated surgically, with an excellent result 2 days after the trauma. End-to-end suturation and a fascial flap plasty were made on both sides. No macroscopic degeneration could be detected on the rupture sites. He was allowed to walk freely 6 weeks after the surgery. The second case was a 54-year-old woman, who had suffered from Achilles tendinitis and peritendinitis for 2 years. Both tendons had been surgically treated, and severe adhesions and local degenerative changes had been found. The tendon rupture occurred when she injured her left ankle while getting out of the car. Two days later she fell at home, because of the weakness of the left side, and consequently the right Achilles tendon was injured. She was treated conservatively for 10 days, before the surgery was performed. Both tendons were ruptured and an extensive degeneration of the area was observed. The right side suffered from a rerupture, which was again treated surgically. After surgery the recovery was slow, but the final result 3 years later was moderate. Neither of the patients had any systemic diseases.     

Evaluation of standardized uptake value to assess cerebral glucose metabolism

PURPOSE: When the cerebral metabolic rate of glucose (CMRglc) is to be measured, arterial blood sampling is usually required for fluorine-18 fluorodeoxyglucose (FDG) and positron emission tomography (PET) studies. However, blood sampling is inconvenient because it requires several staff members and is invasive for patients. METHODS: To assess cerebral glucose metabolism by a noninvasive and simplified method, the authors used the standardized uptake value (SUV), which requires no input function or blood sampling. The study participants included 18 healthy volunteers (4 men and 14 women; mean +/- SD age, 68.2+/-6.3 years), 18 patients with mild Alzheimer's disease (AD) (4 men and 14 women; mean +/- SD age, 68.8+/-7.3 years), and 18 patients with moderate AD (5 men and 13 women, mean +/- SD age, 69.5+/-8.5 years). Regional CMRglc and regional cerebral SUV were measured in the three groups using FDG PET, and the correlation between global CMRglc and global SUV was estimated. RESULTS: The correlation coefficients of global CMRglc and global SUV in the healthy volunteers, mild AD patients, and moderate AD patients were 0.82, 0.67, and 0.62, respectively. Compared with the healthy persons, the patients with mild AD showed significantly decreased CMRglc in the temporal, frontal, and parietal cortices, but they did not show significantly decreased SUV in any region. Patients with moderate AD had significantly decreased CMRglc in the temporal, frontal, occipital, parietal, and sensorimotor cortices and significantly decreased SUV in the temporal, frontal, occipital, and parietal cortices. CONCLUSION: The SUV would be useful as a semiquantitative index of cerebral glucose metabolism only in healthy persons or those with mild AD.     

In situ microdialysis in tendon tissue: high levels of glutamate, but not prostaglandin E2 in chronic Achilles tendon pain

This investigation was to our knowledge the first to use the microdialysis technique to study concentrations of substances in a human tendon. In four patients (mean age 40.7 years) with a painful nodule in the Achilles tendon (chronic Achilles tendinosis) and in five controls (mean age 37.2 years) with normal Achilles tendons (confirmed by ultrasonography) the local concentrations of glutamate and prostaglandin E₂ were measured under resting conditions. A standard microdialysis catheter was inserted into the Achilles tendon under local anesthesia. Sampling was performed every 15 min over a 4-h period. The results showed significantly higher concentrations of glutamate in tendons with tendinosis than in normal tendons (196 ± 59 vs. 48 ± 27 μmol/l, P < 0.05), and there were no significant changes in glutamate concentration over the period of investigation. There were no significant differences in the mean concentrations of prostaglandin E₂ (83 ± 22 vs. 54 ± 24 pg/ml) between tendons with tendinosis and normal tendons. In conclusion, in situ microdialysis appears a useful method to study certain metabolic events in tendon tissue. The higher concentrations of the excitatory neurotransmitter glutamate in Achilles tendons with a painful nodule may possibly be involved in the pain mechanism in this chronic condition. Furthermore, there were no signs of inflammation in the tendons with painful nodules, as indicated by the normal prostaglandin E₂ levels. Received: 30 March 1999 Accepted: 30 May 1999     

Do spinal cord injuries adversely affect serum lipoprotein profiles?

OBJECTIVES: Previous reports indicate that dyslipidemia is very common in persons with spinal cord injury. This study aimed to examine the relationship between spinal cord injury and serum lipoprotein profiles. METHODS: We assessed 28 healthy control subjects matched for age and sex and 60 persons (46 men and 14 women; mean age, 28.1 years) with spinal cord injury having a mean duration of injury of 3.6 +/- 0.8 years (range, 1-13 years). RESULTS: Serum low-density lipoprotein cholesterol level was higher (109 +/- 37, 91 +/- 23.7 mg/dL, respectively) (p = 0.04) and serum high-density lipoprotein cholesterol level was lower (33 +/- 7.1, 44 +/- 7.4 mg/dL, respectively) (p < 0.001) in the patients with spinal cord injury than in the control. Apolipoprotein A-I level was significantly low (94 +/- 10.3, 103 +/- 11.5 mg/dl) (p = 0.003) and apolipoprotein B level was significantly high (93 +/- 15.6, 81 +/- 13.7mg/dL) (p = 0.004) in the group of spinal cord injury. No significant difference was observed the other parameters of these two groups. CONCLUSION: Our results have shown that serum lipoprotein level should not be ignored for the follow-up of the patients with spinal cord injury.     

Avoiding sural nerve injuries during percutaneous Achilles tendon repair

BACKGROUND: Sural nerve injury is a reported risk during percutaneous repair of the Achilles tendon. HYPOTHESIS: Exposure of the sural nerve during percutaneous repair can minimize the risk of nerve injury. STUDY DESIGN: Case control study; Level of evidence, 3. METHODS: The authors retrospectively examined the results of 84 patients who were treated for acute Achilles tendon rupture at 2 different hospitals. Both hospitals used the same percutaneous repair technique, except that the sural nerve was exposed in the 38 patients (mean age, 38 years; range, 23-68 years) of one hospital; the nerve was not exposed in the 46 patients (mean age, 42 years; range, 24-71 years) of the other hospital (the nonexposure group). RESULTS: All patients recovered and returned to work after 44 days (range, 5-202 days). All patients returned to their previous sports levels within 1 year. On the 100-point Hannover Achilles Tendon Score, the mean score was 81 points (range, 44-100 points). The overall incidence of sural nerve related complications was 18%. All sural nerve lesions occurred in the nonexposure group. In the total study population, there were 3 cases of deep vein thrombosis, 1 rerupture, and 1 case of infection. CONCLUSION: Sural nerve injuries can be minimized during surgery by carefully placing the stab incisions to expose the nerve so as to avoid it during repair. If the sural nerve is exposed, percutaneous repair of the ruptured Achilles tendon is a safe and reliable method of treating Achilles tendon ruptures.     

Effects on neovascularisation behind the good results with eccentric training in chronic mid-portion Achilles tendinosis?

The background to the good clinical results reported using painful eccentric calf-muscle training as treatment for chronic painful mid-portion Achilles tendinosis is not known. Recently, using ultrasound and colour Doppler technique, we showed that painful tendinosis was associated with a local neovascularisation. Furthermore, in a pilot study, destroying these neovessels by sclerosing therapy cured the pain in most patients. Dynamic ultrasound and colour Doppler examination has shown that the flow in the neovessels stops during dorsiflexion in the ankle joint. Therefore, it was of interest to study the occurrence of neovascularisation before and after eccentric training. Forty-one tendons in 30 patients (22 men and 8 women, mean age 48 years) with chronic painful mid-portion Achilles tendinosis were examined with ultrasonography and colour Doppler, before and after 12 weeks of eccentric calf-muscle training. Before treatment, there was a local neovascularisation in the area with tendon changes (hypo-echoic areas, irregular fibre structure) in all tendons. At follow-up after treatment (mean 28 months), there was a good clinical result (no tendon pain during activity) in 36/41 tendons, and a poor result in 5/41 tendons. In 34/36 tendons with a good clinical result of treatment there was a more normal tendon structure, and in 32/36 tendons there was no remaining neovascularisation. In 5/5 tendons with a poor clinical result there was a remaining neovascularisation in the tendon, and in 2/5 tendons there were remaining structural abnormalities. In conclusion, in patients with chronic painful mid-portion Achilles tendinosis, a good clinical result after eccentric training seems to be associated with a more normal tendon structure and no remaining neovascularisation. Action on the area with neovessels during the eccentric training regimen might possibly be responsible for the good clinical results.     

US appearance of the rotator cable with histologic correlation: preliminary results

PURPOSE: To characterize the ultrasonographic (US) appearance of the rotator cuff cable in asymptomatic shoulders and in cadaveric specimens, with histologic comparison for the latter. MATERIALS AND METHODS: The cadaveric portion of this study was approved by the institution's Anatomical Donations Department. Institutional review board approval and informed consent were obtained from asymptomatic volunteers and clinical patients for the HIPAA-compliant portion of the study. Four fresh cadaveric shoulder specimens (two male subjects, 40 and 50 years old) were dissected, assessed for the presence of the rotator cable, and imaged with 12-MHz US. Histologic slides (hematoxylin-eosin stain) from three resected rotator cuff tendons were inspected for fibers in the expected location and orientation of the rotator cuff cable. The shoulders in 17 asymptomatic volunteers (seven men, two women; age range, 27-66 years; mean, 41 years) and contralateral asymptomatic shoulders in 10 patients (six men, four women; age range, 24-78 years; mean, 49 years) were scanned and evaluated for the presence and appearance of the rotator cable. RESULTS: The rotator cable was identified at gross dissection. Histologic examination and US of the cadaveric shoulders demonstrated an articular-sided fibrillar structure perpendicular to the rotator cuff tendon (average thickness and width, 1.2 mm and 4.5 mm, respectively). US of asymptomatic shoulders depicted a similar fibrillar structure in three (11%) shoulders up to 1.1-1.5 cm medial to the greater tuberosity (average thickness and width, 1.2 mm and 4.5 mm respectively). CONCLUSION: The rotator cable can be depicted with US.     

Lumbar disk herniation: do MR imaging findings predict recurrence after surgical diskectomy?

PURPOSE: To retrospectively evaluate if the degree of disk degeneration and disk herniation volume at magnetic resonance (MR) imaging are risk factors for recurrent disk herniation. MATERIALS AND METHODS: The institutional review board permits such retrospective studies, and individual informed consent was not required. MR imaging findings obtained before initial diskectomy in 30 patients (mean age, 42.8 years; 10 women, 20 men) with recurrent disk herniation (study group) and 30 patients (mean age, 42.2 years; nine women, 21 men) without recurrence for at least 2 years after surgery (control group) were compared. Disk degeneration was assessed on T2-weighted sagittal MR images with a five-point grading system (grade I indicated no degeneration; grade II, horizontal hypointense bands within disk; grade III, inhomogeneous disk with intermediate signal intensity; grade IV, no distinction between inner and outer parts of disk; and grade V, collapsed hypointense disk). Disk herniation was classified as representing protrusion, extrusion, or sequestration. The volume of both the affected intervertebral disk and the herniated disk material was measured. Qualitative and quantitative analyses were performed by two readers. The chi(2) test was used for comparison of categorical variables. For comparison of disk degeneration and volumes between patients with and those without recurrence, a paired two-tailed t test was used. Odds ratios based on the extent of disk degeneration were calculated for the entire sample. RESULTS: Advanced disk degeneration (grades IV and V) was significantly less frequent in the study group than in the control group (P < .006). The risk of recurrent disk herniation decreased by a factor of 3.4 for each increase in grade of disk degeneration (odds ratio: 3.58; 95% confidence interval: 1.3, 9.6; P = .011). Mean disk herniation volume as a percentage of intervertebral disk volume was 10.59% +/- 3.41 in the study group and 11.56% +/- 3.84 in the control group. This difference was not significant (P = .31). CONCLUSION: Minor disk degeneration but not herniation volume represents a risk factor for the recurrence of disk herniation after diskectomy.     

Achilles tendon adaptation during strength training in young adults

PURPOSE: Tendons are specialized musculoskeletal structures responsible for transferring forces between muscles and bones. To maintain joint mechanics and structural integrity, tendons must adapt to changes in mechanical loading, but little is known about the interaction between muscle and tendon adaptations in vivo. We tested the hypothesis that tendons adapt to changes in muscle strength to maintain strains within a preferred operating range. METHODS: The right lower leg of 10 male subjects, age 24.9 +/- 3.4 yr (mean +/- SD), mass 78.1 +/- 9.7 kg, and height 176.5 +/- 7.2 cm, were tested before and during weeks 1, 2, 4, 6, and 8 of an 8-wk ankle plantar flexion strength training program. Subjects performed isometric plantar flexion efforts slowly ramping up from rest to a maximum effort. Plantar flexion force, Achilles tendon deformation, and cross-sectional area were measured. Triceps surae muscle force (assumed equal to Achilles tendon force), normalized force, and Achilles tendon stress and strain were calculated. Achilles tendon strains during maximum plantar flexion efforts (epsilon(max)) were compared between weeks to test the hypothesis. Repeated-measures ANOVA was used to test for significant changes during the 8 wk, with alpha = 0.05 used as the criterion for significance. RESULTS: There were no significant differences in the group's mean percent or absolute change in epsilon(max) (P = 0.607 and 0.351, respectively) despite a 21.4% average increase in muscle strength during the 8 wk. CONCLUSIONS: This is the first study that quantifies Achilles tendon strain throughout a strength training program. Findings indicate that the Achilles tendon adapts quickly to muscle strength training and experiences relatively little change in peak strain despite large increases in muscle strength.     

Effect of heparin on tendon degeneration: an experimental study on rats

This study investigated the local effects of heparin on locally administered corticosteroid-induced experimental Achilles tendinitis. After performing Achilles degeneration, 28 rats were divided into two groups; one was treated with local heparin and the other with saline injections at 3 and 6-day intervals. The tendons and paratenons were excised after 60 or 75 days and evaluated histopathologically and statistically. Heparin-injected tendons and paratenons demonstrated significantly higher scores for most compared groups, thus worsening the degeneration. At the second part of the research, eight healthy tendons were injected with heparin at 3-day intervals for 1 month, and seven of them showed various degrees of degeneration. Heparin itself thus has a degenerative effect on the tendon and should not be used in the treatment of Achilles tendon degeneration.